


Morning Surprises

by VelourFanClub (toomanysorrows)



Category: Monster Girl Encyclopedia, Monster Girls | Monster Boys
Genre: F/F, Modern AU, Physical Transformation, Transformation, concerned girlfriend, creepy ladies in spooky mansions, monster girl transformation
Language: English
Status: Completed
Published: 2020-06-01
Updated: 2020-06-01
Packaged: 2021-03-03 01:00:48
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,294
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24496117
Author URL: https://archiveofourown.org/users/toomanysorrows/pseuds/VelourFanClub
Summary: You've been dating your hellhound girlfriend for a while now, and recently moved in together. One morning you wake up to a surprising sight in the mirror.
Relationships: Reader/Hellhound
Comments: 8
Kudos: 57





	Morning Surprises

**Author's Note:**

> So, one thing that's pretty obvious when you're reading monster girl encyclopaedia lore: it's very, very heteronormative. And that got me thinking, how would some of the lore affect monster girls and their partners if they're in a sapphc relationship? And from that thinking this concept was born.
> 
> Won't get into the details of what happens since, y'know, that's in the fic. That said one thing I wanna make clear is that this is very much not meant to be canon compliant. It's not so much me writing in the established universe as it is me pilfering shit I like from it to explore an idea I had.

“Babe?”

“Yeah?”

“Do you know why my eyes are on fire?”

A loud bang sounded from the kitchen. Great, now you’d have to clean up whatever that was too… You heard the sound of your girlfriends clawed feet on the floor as she hurried over to the bathroom. In the meantime, you had some time to inspect your… new appearance in the mirror. Right where yesterday there had been two perfectly normal, human eyes, there were now two black pupils staring at you from a sea of dark fire. There were even small, harmless licks of flame flickering from out of your eyes, like a weaker version of the flares your hellhound girlfriend had there. 

“What do you mean your eyes are on fire?!”

You turned around to look at your girlfriend Roxanne, who immediately gasped as she saw your eyes.

“Shit, how the hell did that happen?”

You shrugged, at a loss for what to say.

“I mean, I don’t know. I went to brush my teeth and they were just… like that.”

As you said that, she narrowed her eyes and came closer, taking your chin in her hands.

“Babe, open your mouth please.”

You were slightly confused by the request but complied. You knew the tone of voice she was using. That one only came out when she wouldn’t take no for an answer.

She reached out one of her finger to poke at your- Teeth? Was that a tooth? They weren’t supposed to be this long, right?

“You have fangs?”

“I have fangs?”

You drew back to look in the mirror again. Indeed there they were, a large set of canine teeth, not human by any stretch of the imagination.

“I have fangs.”

“You have fangs.”

Both of you just stood in silence in the bathroom for a while, baffled by this turn of events. Roxanne suddenly stood up and left the bathroom.

“Get dressed, we’re going to the hospital.”

\----

The hospital visit cleared nothing up, except for the fact that for all intents and purposes you were healthy. Just with new eyes and teeth. Even the doctors specializing in arcane illnesses only had some vague theories, none of which were likely in your situation. Basically you were a medical mystery. This of course meant all kinds of tests, and it was when they were going to put a tube through your nose that both you and Roxanne decided enough was enough and left the hospital. 

Back in the car you sat down and put on your seatbelt.

“So, what do we do now? It’s nearly lunch, maybe we should grab something to eat in town?” 

Roxanne shook her head.

“Nuh-uh. We’re getting this figured out. We’re going to madame Cassilda.”

You knew about madame Cassilda. Hell, everyone in town knew about madame Cassilda, even the people who weren’t close to the monster girl population. It was kind of hard to ignore the extravagant, centuries-old mindflayer. She lived in an ancient mansion on a hill at the edge of town. You know, the kind that’s next to a graveyard and that gets ominously illuminated with lightning any time someone looks over? She’d been something of an urban legend for a while now, with kids daring each other to try to climb over the walls surrounding the mansion. 

You’d never actually met her, but you knew Roxanne had. She was sort of the grande dame of the local monster girl community and people often went to her for advice. Well for that and for the parties she sometimes hosted for them. According to rumours she was incredibly magically gifted so the idea of going to her about this seemed to make sense. Although you couldn’t help but be a bit apprehensive, given her reputation…

\----- 

“Honey are you sure about this?”

You looked over at the mansion. True to form, dark storm clouds had already gathered above it. 

“I know she doesn’t have the best reputation, but she’s the smartest woman I know. If anyone can figure this out, it’s her. Plus, I’ll be here to keep you safe right?”

She smiled down at you, looping an arm around your shoulders. You sighed, giving her a weak smile and nodding.

“Alright. Let’s go then.”

You both walked up to the big gate and Roxanne rang the buzzer. A husky, slightly uncanny voice rang out over the intercom.

“Yes, who is it~” 

“It’s Roxanne, madame Cassilda. I uh, we need some help.”

“Oh Roxanne! Of course, come in. The front door is unlocked. Just head to the library!”

Before your girlfriend could reply the buzzer clicked off and the gates opened with a slow, dramatic creaking sound. Hesitantly, you followed Roxanne in.

\---- 

The inside of the house didn’t do anything to calm your nerves. The foyer and hallways had been nice at first glance, although old fashioned. But on closer inspection those plants definitely didn’t look like anything you’d seen before and some of those glass bottles had weirdly shaped things in them. And then there were the paintings... You leant just a bit more into Roxanne, who hugged you close.

Eventually you two reached the library and Roxanne went in ahead, poking her head through.

“Madame Cassilda?”

“Ah yes, here dear! Come in, come in!”

You followed Roxanne into the library. It was impressive to say the least. The walls were literally covered with books, in some cases double rows of them and- wait, did that book just move?

A woman stood up from a sofa, a book in hand. It was clear from the mass of writhing tentacles coming out of her head and her purple skin that she was the lady you’d come for.

“Welcome, welcome! I would ask what the problem is, Roxanne, but given your friends eyes I think that’s rather obvious.”

Your girlfriend nodded awkwardly.

“Yeah uh, do you know what might have caused that? We’re kinda worried.”

“Maybe, maybe.”

Madame Cassilda came closer and started walking around you, scrutinizing you from several angles

“Tell me dear girl, have you been in contact with any suspicious magical artifacts lately?”

You shook your head.

“No. I try to avoid that sort of thing.”

She sighed dramaticaly, shaking her head.

“I swear, people don’t appreciate nice, old fashioned black magic anymore.”

She looked you two over, a smirk coming over her face.

“Roxanne dear, given the way you’re holding her, I assume this is that girl you told me about?”

You blushed, and from Roxanne’s tone you knew she did too.

“Uh yeah. We moved in like two months together.”

“Marvellous, marvellous.” 

The mindlayer started gathering books of the shelves into a small stack.

“Now, I do have a working theory, but I’ll have to review some material first. Don’t worry, it shouldn’t be too long. Thomas!”

There was the patter of feet as someone hurried towards the library. Eventually a small man poked his head in.

“Yes love?”

“Please bring our guests some tea. Oh, and maybe some sandwiches, they must be starving at this hour!”

She smiled over at you two.

“Thomas’ cooking is simply to die for. And I’m sure he’ll appreciate the chance to make something not involving brains for once!”

Thomas smiled, confirming madame Cassilda’s comment.

“Of course! I’ll have some right up!”

With that he went off and madame Cassilda picked up the stack of books she’d gathered.

“Well, I’ll be a couple of hours. Please, make yourself at home. But try to avoid the top shelves if you want to read. The once further up are… not healthy, let’s put it that way.”

With that ominous warning, you two were left alone. 

\----

Two and a half hours and a surprisingly ordinary meal of tea and sandwiches later, miss Cassilda came waltzing in, a satisfied grin on her face.

“I do believe I have found the explanation for what you’re experiencing.”

She sat herself down in a big armchair opposite you two, smiling and connecting the tips of her hands.

“As I’m sure you are aware, all monster girls give off a certain amount of demonic energy. The amount most people experience is negligible and therefore doesn’t affect them. But humans who come into contact with us a lot, particularly physical contact,” she winked, “the effects will be greater. Especially since such ‘physical contact’ dramatically increases our energy output.”

You turned red and from the flaring of Roxanne’s eyes it was clear she was just as embarrassed. Madame Cassilda just kept explaining, albeit with a broad grin.

“Now, the effects of the energy are highly gendered. Men generally experience increased stamina, sensitivity and desire, resulting in the infamous ‘heat cycles’ human men and monster girls in a relationship go through. For those outside the binary the effects are… nebulous. There’s a large variety of genders in that category, and very little data. But the effects on women is when it gets interesting. You see, the corrupting effects of demon energy mainly serve for helping the species multiply. With men this is done by simply increasing the desire for sex, in the hopes of producing more offspring. With women however, it does this by turning them into monster girls.”

You sat up a bit in the chair as you listened, the information surprisingly interesting. You’d never really realised the mechanics of demonic energy were that intricate, figuring it was just something for fun…

“Now, this ability to reproduce through the corruption of human women is only fully developed in some species, in many it has atrophied on account of the fact that sexual reproduction is both more pleasurable and beneficial in the long run. But the effect is still present in subtle ways, even among the species where it is no longer employed for reproduction. Now the effects of casual exposure to demonic energy on human women as a result of proximity to a human woman, as opposed to a deliberate corruption, has not been studied much. As a group we typically prefer men, so relationships are rare, and since the children of such unions are always monster girls human women are just not often in such close contact with us. Barring any unorthodox family or friendship arrangements of course.  
But in summary I do believe that these changes are simply the natural effect of you having a monster girl as a lover, my dear.”

You blinked. Well. The explanation did make sense.

“So, am I gonna change into a hellhound?”

Cassilda shook her head.

“It won’t be quite so drastic. If you were dealing with a species whose energy was much more mutagenic, like a kitsune or mucus toad, I would expect such a result. But hellhound energy is rather weak in this regard. If your relationship continues there will likely be a few more, such as more body hair in the appropriate places or perhaps claws much later on. But I doubt it’ll be more than that. You simply don’t have the lifespan to get exposed to enough of her demonic energy to undergo a full transformation.”

You nodded, taking it all in. You glanced over towards Roxanne, immediately noticing how tense she seemed.

Madame Cassilda seemed to notice it as well, standing up again.

“Well, it seems to me like you two might have something to talk about. Of course, my door is always open for any more questions you have! In fact, I’d love to hear updates on this situation, as it is so unique. But it is getting quite late, so that will be a conversation for another time I’m sure. Do have a safe journey home.”

The audience clearly over, you two walked back to your car.

\---- 

The car ride was tense and silent. There was something bothering Roxanne, that was clear. Eventually you asked her to just park at the next spot available. Once the car had stopped, you turned to her, a concerned look on your face.

“Something’s eating at you honey. What’s wrong?”

Roxanne bit her lip.

“I mean, you’re gonna want to break up with me now, right? And that isn’t like, a guilttrip, because I wouldn’t blame you for it. I’m just.. waiting for the shoe to drop isn’t fun, ya know?”

Gods, where did she get that idea from? You reached out to take her hand, squeezing it in reassurance.

“Aw babe, of course I’m not breaking up with you.”

She frowned.

“But if we continue dating you’ll just continue to be less and less human…”

You shrugged. 

“Eh, I won’t fully transform and the biggest changes have already happened it seems. And I don’t mind them, really.”

She arched her eyebrow, confused.

“You don’t? How?”

“They don’t impede my speech or my sight, they look really cool and the teeth are great for eating gamey steak. I don’t see any downsides, personally.”

You grinned, exposing your new acquisitions to show you really were comfortable with them. After a while Roxanne couldn’t help but let out an incredulous laugh.

“God, I should’ve known. There could be a zombie invasion and you’d still be laid-back about the whole thing.”

You chuckled, happy to have gotten the tension out of the air

“Oh you love it. And besides,”

You leant in closely to plant a peck on her cheek.

“I think bigger teeth are a cheap price to pay for getting such an amazing girlfriend.”

Her eyes flared and her cheeks turned dark. You giggled as she shoved you away.

“Gods how did I end up with such a sap.”

The smile on her face didn’t match her grumpy reaction. You had a grin on your face for the entire ride back. This had resolved itself very well and you could already think of some very fun things to use those new fangs for~


End file.
